Eco-friendly approach utilizing green synthesized nanoparticles for paper conservation against microbes involved in biodeterioration of archaeological manuscript

Potential high bio-deterioration of certain microorganisms due to their metabolic activities on organic materials causes serious problems in the conservation of cultural heritage. This study focuses on establishing an efficient conservation strategy against microbial deterioration using biosynthesized nanoparticle (NPs). Isolation, identification, and characterization of microorganisms involved in deterioration of archaeological manuscript dating back to 17th century (1677 A.D) were conducted. Eleven bacterial species and fifteen fungal species were obtained and identified using 16S rRNA and ITS sequences, respectively. All strains exhibited potent cellulolytic activity. Bacillus subtilis strain (B3) and Penicillium chrysogenum strain (F9) achieved the highest cellulolytic activity amongst obtained bacterial and fungal strains. Paper models conservation effect of biosynthesized silver and zinc oxide NPs against strain (B3) and strain (F9) was evaluated. Microbial growth inhibition, color change according to CIE L*a*b* color space, fourier transform infrared spectroscopy (FT-IR) were assessed. Furthermore, morphology and the elemental component of paper models were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Silver NPs achieved better results than zinc oxide NPs for paper preservation. Application of 1.0 or 2.0 mM silver NPs exhibited the best preservation effect on the paper models achieving 100% microbial inhibition (bacteria and fungi, respectively). Moreover, NPs-treated paper models showed slight color change and exhibited similar structural analysis as original papers. These results showed the potentiality of this green strategy to be applied for conservation of cellulose-constructed cultural heritage.